The motor stators or the magnetic actuators for magnetic bearings cannot always be centered and fastened to their housing using fasteners such as screws or rivets. To reduce the size of the assembly or to facilitate its manufacturing, the stators are often shrink fitted to their housings. A shrinkage interference of the diameters of the stator and the housing must be computed relative to the size of the parts or the environmental conditions of the assembly on the basis of the thermal elongation of the materials used.
Currently the shrinkage of two assemblies or of an assembly into its housing is done by thermal expansion. The external assembly or the housing is heated to a certain temperature to obtain an expansion bigger than the shrinkage value, allowing a free insertion of the inner assembly, and then the two parts are cooled to the same temperature to obtain the shrinkage.
This current method requires a heater which needs to be in accordance to the size of the parts to be heated and high precision during the insertion to prevent a partial shrinkage. When the parts get stuck at a wrong position, the assembly is lost, since the only way to recover some parts is to destroy the assembly. The final position of an assembly of this kind is often fixed by a shoulder that gives the final position and no adjustment is possible.